Adjustable shelf



FIG. 1 is a perspective view of the present invention;

FIG. 2 is a front side view of the present invention;

FIG. 3 is a back side view of the present invention;

FIG. 4 is a left side view of the present invention;

FIG. 5 is a right side view of the present invention;

FIG. 6 is a top side view of the present invention; and,

FIG. 7 is a bottom side view of the present invention.

The broken lines shown in the drawings form no part of the claimed design. 

CLAIM The ornamental design for the adjustable shelf, as shown and described. 